Tomato on RT-AC68U with physical connection to the gateway router. I want IP address to be 192.168.4.4/24

I should be able to administrate Tomato from clients connected to the DD-WRT router and also connected to Tomato ethernet ports.

Enable whatever multi-cast capabilities on Tomato as required by Chromecast and Belkin WeMo power plugs. (<—- end goal)

My expected configuration steps are:

Configure Wifi. Enable multicast.

Disable WAN port

Configure Tomato as a router so it will route Wifi to LAN (should be default?)

Hard wire Tomato's IP address to 192.168.4.4/24

Disable DHCP running on Tomato

Save/reboot Tomato router

Connect Tomato router to DD-WRT router through LAN port

Test wifi receive an IP address from DD-WRT. Test wifi address can be pinged from DD-WRT. Drink beer and celebrate.

Any problems with my expected steps above?

Here are the problems I am having…

First, I can't find how to configure the static IP address for Tomato. Is this "Route Modem IP" and do I have to have the WAN enabled to configure this? Or do I configure it on the bridge? (I am guessing the bridge is not the appropriate place to set the IP address)